So...from the article:
Before Interxion started the project, its energy bills were about $2.6 million a year to cool 1 megawatt of IT load. Today, its energy bill is $5.4 million to cool 5.5 megawatts of IT load, meaning the system has saved it about $1 million a year.
So "today" per 1MW of IT load, it would cost $5.4million / 5.5MW or $981818.18 ( 54/55 million $ per MW or 0.981818182 x million $ per MW)
$2.6 million - $0.98 million > $1 million
Now, if he wanted to cool 5.5MW of IT load, it would cost him $14.3 million with the old method vs $5.4 million with the seawater method.
Even if you account for the cost of the third-party...$14.3 million vs $5.4 million is a big difference.